1. Technical Field
The present invention relates to a cap member of a liquid discharge head, a liquid discharge device, and an image forming apparatus including the liquid discharge device.
2. Related Art
Inkjet recording methods using a recording head to discharge ink droplets onto a sheet-like recording medium such as a sheet of paper or a film are well known. The recording device typically employs a cap structure including a cap capable of sealing an ink discharge surface of a head; and an ink-absorbing member capable of absorbing ink discharged or absorbed from the recording head.
The ink is discharged from a plurality of nozzles, the dischargeability of which is degraded due to, for example, drying out. In order to maintain good dischargeability, there are two ways that the cap structure operates: when (1) ink discharge surface is sealed and ink is absorbed from the nozzle, by decreasing the pressure within a sealed space; and (2) the ink discharge surface is not sealed and the recording head is caused forcibly to discharge ink (i.e., a dummy discharge operation).
To reduce the time required to reduce pressure inside the cap, the cap has been made smaller. In addition, dummy discharge performed before, during, and after printing is executed in a state in which the cap is separated from the ink discharge surface, that is, in a state in which the discharge surface is not sealed, to improve productivity.
Further, to facilitate removal of paper jams, allow operators to see the head while cleaning the discharge surface, and prevent smearing of the sheet surface due to ink drops from breakage of the discharge surface meniscus, the discharge surface is sometimes oriented vertically, in a so-called horizontal ink-jetting method. In such a configuration, the cap structure tends to be disposed similarly vertically to simplify the structure and reducing the number of parts used. Dummy discharge is performed in a state in which the cap is closed to prevent leakage of the discharged ink outside the vertically disposed cap.
However, for the purpose of improving printing performance, when dummy discharge is performed by the horizontal jet method in a state in which the cap is separated from the ink discharge surface, the discharged ink is not held inside the cap so that the ink is leaked outside the cap.
The ink leaked outside the cap adheres to the cap nip portion, thereby decreasing a pressure reduction effect inside the cap and degrading the image quality because the leaked ink adheres to the recorded medium via the discharge surface.
JP-2001-65309-A discloses provision of a cap member closely connected to an interior wall of the cap to prevent the ink from leaking from the cap. However, this approach has certain disadvantages, such as an increase in cap size due to addition of the cap member, lengthening of the period of time needed to decrease the pressure in the cap, and increase in the number of parts.